Gaskets are used in many applications to form mechanical seals. In automotive applications, many gaskets are formed from one or more foam sheets. Such foam gaskets may bend into nooks and crannies in various irregularly shaped gaps and/or voids in any of a number of automotive structures.
Historically, foam gaskets in automotive applications are solid rather than hollow. “Solid” as used herein includes sheets of foam material, even though air is trapped in cell structures. For example, a sheet of foamed polyurethane is “solid.” “Solid” foam sheets includes sheets of constant or substantially constant density, varying density, or combinations thereof. Air in cells of the foamed material is outside of the definition of “encapsulated air” or “air filled pocket” as used herein.
It is understood that use of solid foam sheets as gaskets can add to material cost and can add weight to a structure where additional weight may not be desired. Thus, gaskets having at least one hollow section may be useful.
Hollow gaskets of various materials have been formed by adhering one previously formed gasket portion to another previously formed gasket portion. This adhering processing has traditionally included manufacturing steps such as die cutting and/or fusion molding. Such additional manufacturing steps may add cost and time to the manufacture of gaskets having at least one hollow section.
Thus, there is a need for light-weight gaskets that use less material and that minimize the weight added to components. There is also a need to maintain relatively simple and/or streamlined manufacturing processes such as those that use existing equipment.